Automatic electric service line protector



Feb. s, 193s. L E, FARRELL 2,107,820

AUTOMATIC ELECTRIC SERVICE LINE PROTECTOR Filed April 3, 193e l 2 sheets-sheet 1 Eig-L Eig-2- 72 e \||l| B ,z3/T l C u 73 72 M Ill, 6 1- 3 u /ff 1 77 Ahn...

ll/Illll Feb. 8, 1938. J, Eb FARRLL 2,107,820

AUTOMATIC ELECTRIOSERVICE LINE PROTECTOR Filed April 3, 1956 2 Sheecs--SheeiI 2 LSQPLEFZY/rrell,

Patented Fe'b. s, 193s 'PATENT OFFICE AUTMATIC ELECTRIC SERVICE LINE PRO- TECTR Joseph E. Farrell, Washington, D. C., assigner to Automotive Devices Corporation, Washington,- D. C., a corporation ci Delaware .duplication April 3, 1936, Serial No. 72,636

8 Claims.

The present invention relates to a device which will automatically function upon thevoccurrence of a short or overload in an electric service line to protect electric devices connected'in the circuit 5 against damage.

A primary object of the invention is to provide novel improvements in a device of the electromagnetic type wherein an electro-magnet becomes energized upon occurence of the unusual condition l in the line thereby automatically and-instantaneously to release means for opening and breaking the circuit.

nother object of the invention is to provide an electro-magnetic circuit breaker which includes a l fusible link set to operate at higherx amperage than that at which the electro-magnet will function, and therefore the lint; will only melt under un usual load. For example it the electro-magnet will function at lil amperee, the fuse selected will not blow unless the load reaches or exceeds l5 amperes. 'in actuai practice, however, it has been found that the electrmmagnetic means ralways functions so quickly that the fuse seldom if ever is called into play, but nevertheless, it is provided as an added or emergency safeguard. Accordingly, the invention provides a combined electromagnetic and fusible type circuit protector wherein the fusible link provides an additional factor of safety and will only become ruptured or 3o broken in the event that extraordinary conditions occur in the line.

A further object of the invention is to provide a screw-plug type construction adapted to t in any screw shell receptacle and which has a mini*- mum length along its axis thereby permitting of its use in any standard fuse box,l fuse panel or other equipment without adjustment or modica tion thereof.

A still further object of the invention is to provide a novel cover for housing a spring tensioned disk or switch block, said cover having ratchet elements cooperating with spring brush terminals which function as pawls, said ratchet elements being a part of insulation barriers adapted to be interposed between the brush terminal elements and the contacts of the switch block sothat ineventA will more readily appear as the nature of theA invention is better understood, the same consists in the novel features of construction, combination 55 and arrangement-of parts hereinafter more fully (Cl. 20G-88) athe line fi--B of Figure 3.

Figure 5 is a top plan view of the plug base.

Figure 6 is a bottom plan view of the cap.

Figure 'l is a diagrammatic view showing the position oi the disk-like switch block and barrier l5 walls carried by the cover when the device is set in the .on position.

Figure 3 is a view similar to Figure 'i snowing the relative position of parte when the current is G. 2G

Figure 9 is a side elevation ot the cover showing more clearly. how the barrier walls are out away to limit the movement of the disk relative to the cover. I

Figure lo is a perspective View of the disk or 25 switch block.

Similar reference characters indicate correspending parts throughout the several figures' of the drawings.

According to the embodiment shown in the 3o drawings the invention includes in its organization a plug body or base A and a cap structure designated generally as B. Theplug body and the cap may each be completed before assembly so that the mere placing of them together brings them 35 into operative relationship. Any suitable means may be employed for holding the cap and base tcgether, such for example, as the ring C or its equivalent.

Referring to the body or plug base A it may be 40 pointed out that the lower portion is surrounded by an external metallic screw shell connector I, while the interior thereof houses an electro-magnet 2. The outer end of the core 3 of the magnet constitutes the center connector 4 of the device. 45 while the upper end is exposed in the bottom of a. recess formed inthe upper part of the base. The winding of the electro-magnet has one end 2l connected tothe core while the end 2b is connected to an upstanding spring brush terminal 5, also housed within the recess formed in the base. An-

' other spring brush terminal 6 is located in the recessed base opposite the contact 5 and is electrically connected as vat 6 with the screw shell l. The spring brush terminals 5 and G are preferably 55 made of spring conducting material and are each formed at their free ends with an inwardly offset contact portion a which also functions as a pawl as will later appear.

Between the contacts 5 and 6, and within the recessed upper portion of the base A there is also provided a spring-biased armature 1. 'I'his armature is preferably in the form of a plate piv- 'otally supported at 8 and normally thrust away from the upper end of the core of the electromagnet by a spring 9. The forward or front end of the armature member 1 is provided with an upstanding detent or lug I0.

The inner side of the cover II is preferably formed with a central post I5 and is also provided with the pendant barrier members or walls I6 and I1. As will be observed from Figures 3 and 4 these walls are located inwardly of the inner 'periphery of the flange or. skirt II thereby to provide a space or channel for receiving the upstanding spring brush terminals 5 and 6. Also these walls are tapered or beveled at their front or toe ends as indicated in I6 and I1, while the rear ends or heels ISb and I1b respectively are squared or shouldered to provide in effect, ratchet abutments to cooperate with the ends b of the spring brush terminals as will presently appear.

The barrier walls I 6 and I1 are also spaced apart to provide a gap therebetween to permit of the offset portions a of the spring brush terminals 5 and 6 engaging with the contacts I8 and I9 carried by an insulating disk or switch block 28. 'Ihe contacts I8 and I9y are connected or bridged by a fuse link 2I embedded in a suitable grcove'or channel in the face of the said disk lying adjacent the inside face of the cover II.

The disk or switch block 20 is preferably chambered at one side as indicated at 2I to fit over the post I5, the diameter of the chamber 2| being sufficient to house and conceal a coil spring 22, one end of which is anchored in the post I5 of the cover, while the opposite end is anchored to the ydisk within the chamber 2l. Prior to assembling the disk 28 on the post it is preferred to place a sheath 23 of mica or its equivalent between the disk or switch block and the inside face of the cover, said sheath serving as a transparent window for the openings I3 and I4 in the cover. For the, purpose of holding the disk or Contact block 20 to the cover any suitable.

detachable fastening may be used such, for example, as the screw 24. Thus, the disk or contact block may be readily renewed if desired.

The disk or block 20 is, of course, made of insulating material and snugly ts within the annuiar space provided between the curved barrier walls I6 and I1. Therefore, the disk is not only supported for arcuate or oscillatory movement relative to the cover by the screw 24, but is also guided in its movement by the walls I6 and I1. The lower face of the disk 20 is provided with diametrically disposed offset lugs 25 and 26 and is also.provided with a laterally or radially cifset arm 21 adapted to move betweenshoulders 28 and 29 formed by cutting away the bottom edges or' the walls I6 and I1, thus hunting the relative movement between the disk and the cover under the tension of the spring 22.

When the device is assembled as shown in Figure 3 it is ready for insertion into any screw shell preferably provided at spaced points with mi?,

designations On and Oli which will successively appear beneath the window I8. The fuse link or conductor 2I may be observed through the window I4.

In the normal service condition of the parts the armature 1 is urged upwardly by the spring 9, so that the lug I8 thereof isy in engagement with one of the lugs, 25, for example, on the bottom of the disk 28 thereby placing the spring under tension The cover II is, prevented from retrograde or backward movement by the ends b of the terminal brushes engaging with the ratchet shoulders |61 and I1b, of the barrier walls I6 and I1 respectively. (See Figure 7.) Thus the contacts I8 and I9 of the disk or switch block are maintained in engagement with the portions a. of the spring brush terminals l and 6. With the parts in this condition the circuit .may be maintained in the line through the center contact I; the winding of the electro-magnet; brush terminal 5; contact I 8; fuse 8|; Contact I9; and brush terminal 6 to the screw shell I.

Upon the occurrence of a short or overload in the line, the switch is tripped in the following wayz-The electro-magnet becomes energized and attracts the armature type latch 1 against the tension of the spring 8 thereby drawing detent Ili of the latch out of engagement with the lug 25 of the switch or contact disk with which it has been engaged. Immediately upon Ill and 25 being separated, the tensioned spring will cause switch disk 20 to move forward and take contacts I8 and I9 away from the free ends of the springs constituting the line terminals 5 and '6, placing them behind the insulating barrier walls I6 and I1. Simultaneously,the radial arm or projection 21 on the switch disk leaves the shoulder 28 on the insulating wall I1 and moves toward the shoulder 29 of the wall I8 (Figures 'I and 8). The effect of 21 striking shoulder 29 is to push or move the cover I I forward so that the ultimate position of parts after the electro-magnet has functioned is that shown in Figure 8. That is to say, when the radial arm or projection 21 of the switch disk strikes the shoulder 29 it will move the entire cover carrying the insulating walls I 8 and I1 so that the bevelled toe portions of the walls will press the free ends of terminal springs 5 and 6 outwardly, thereby to be ready for the next snap engagement of the springs with the contacts I8 and I9 upon the resetting of the device.

As will be apparent by comparison of Figures 'I and 8, the lug 25 on the exposed face of the switch disk movessubstantialiy from the position shown in Figure I to that shown in Figure 8 when the electro-magnet causes the release of parts III and 25. Therefore, the lug 26 will be the next lug to engage the detent I8 of thear- Ymature type latch 1.

out of the path of lug 25, it will, of course, be understood that if the short or other condition in the line has been removed, the device may then be reset by rotating the cover II. In resetting, the initial movement of 4the cover is idle in the sense that the cover and the insulation walls I6 and I1 carried therewith may move a certain distance before the lug 28 in the switch disk again engages the detent I8 of the latch. 'Ihe detent Il of the latch is, of course, in its upper position que to the deenergization of the electrovis magnet and, therefore, lies in the path of the oncoming lug 26. When 26 engageswith I0, the turning of the cover winds the spring 22 and the switch disk and the Cover are again tensioned. When radial arm 21 engages with the shoulder 28, the ends I6b and I'Ih of the members I6 and I1 release the free ends of the terminal springs 5 and 6 causing them to snap into the clearances provided between each insulating barrier wall I6 and il, thereby to engage again with contacts I8 and it which, meanwhile, have been brought into position to be exposed through said clearances. Therefore, the 'various parts again assumethe normal relation shown in Figure 7. From this figure it will be apparent that the mutually tensioned switch disk and cover are y respectively held in their locked positions by the lug 26 on the switch disk engaging with the detent I of the latch and because the free ends of the terminal springs and 6 engage behind the ratchet shoulders ib and lib of the insula-n tion barrier walls.

In the event that the short or overload persists in the line, it will be impossible to reset the device because immediately upon terminal springs 5 and 6 engaging with contacts i8 and I9 of the switch block, the circuit through the device will be re-established, thereby energizing the electromagnet `which will immediately pull the latch type armature i downwardly so that the detent lil is out of the path of either of the lugs or 26.

In the event that the overload is greater than the amperage at which the electro-magnet will function, it will, oi course, be understood that the fusible conductor or connector 2i will blow and thus fully protect the line in which the device is installed;

In the event that the :fusible conductor 2i for the contacts i8 and i9 becomes ruptured or broken, it is possible to readily replace a new switch disk in the cover by simply removing the fastening 24 and reinserting a new dislrwitli a fresh fusible connector. rihereiore, the device as a whole need not be discarded but may be readily replaced in serviceable condition by sim ply renewing the switch disk 2d.

Without further description it is thought that the features and advantages of the invention will be readily apparent to those skilled in the art, and it will of course be understood, that changes in the form, proportion and minor details of construction may be resorted to, without departing from the spirit .of the invention and scope of the appended claims.

1, An electric service line protector including in combination, an armature type latch normally spring biased to latching position, an electromagnet for actuating the latch, a pair of oppositely located spring terminals, a' switch disk overlying the latch and having means for engaging therewith, said switch disk having opposite contacts connected by a fusible conductor adapted to carry an amperage substantially higher than the amperage for which the electro-magnet is set `to function.

2. An electric service line protector including,

, in combination, a latch spring-biased to latching position, an electro-magnet for the latch, yieldable line terminals mounted to have their free ends to function as pawls, a two-part rotatable cap unit including a cover and a disk rotatably connected and said disk carrying contacts connected by a fsible conductor, said vcover and disk being also connected by a coiled tensioning spring, and said disk having means to engage said latch, and ratchet means von said cover for engaging the pawl ends of the line terminals.

3. .An electric service line protector including, in combination, a latch spring-biased to latching position, an electro-magnet for the latch, a pair of combined pawl and line terminal elements, a rotatable cover having ratchet shoulders thereon for cooperating with said terminal elements to compel movement of the cover in one direc-'- tion, a disk, conductor means on the disk for bridging said line terminals, a coil spring for connecting the disk to the cover, said disk having means cooperating with the cover to limit its movement relative thereto, and means on the disk for engaging the latch to tension the coil spring when ythe ratchet shoulders on the cover are in abutting engagement with the combined terminal and pawl elements, thereby .to cause the conductor means onv the disk to complete a circuit between the line terminal elements.

An electric service line protector-including, in combination, a base having spring line-terminal members, a latch spring-biased to latching position, an electro-magnet for said latch, a roiatable cover having ratchet shoulders cooperatn ing with the ends of said terminal members to compel movement of the cover in one direction, a dislr within the cover and having contacts bridged by a conductor, a coil spring for connecting the disk with the cover, and means on the disk for engaging with the latch for tensioning the disk relative to the cover and also normally to maintain the contacts on the dislr in engagement with the terminal members'.

5. .ein electric service line protector including, in combination, an electro-magnet, a pair of spring brush terminals, one oiwhich is included in circuit with said electro-magnet, a spring biased armature-type latch responsive to a eld generated by the electro-magnet, a `rotatable cover having abutments thereon, a switch disk mounted on the cover and movable between said abutments, a spring connecting the dist: and

cover, means on the disk for engaging said latch, a pair ci contacts on the switch disk for engaging said terminals, and a fusible conductor connecting said contacts.

6. An electric service line protector comprising, in combination, a base, an electro-'magnetic latch thereon, upstanding brush terminals on the base, a cover rotatably'held to the base, insulating barrier walls carried by the inside face of the cover and projecting therefrom into the zone of the upstanding brush terminals, said walls being spaced from each other at their ends, and one adjacent pair of ends being notched to provide abutment shoulders, a switch disk housed within the said walls, a radial arm on the disk for alternately engaging with said shoulders, a coil spring for connecting the disk to the cover, and contacts carried by the disk and connected by a fusible conductor.

7. An electric service line protector comprising, in combination, a base of insulating material, an electro-magnetic .latch on the base spring-biased to normal position, lineV terminals at opposite sides of the base and comprising ups'tanding spring members with free end portions, an insulating cover rotatably held to the base, arcuate insulation walls on the cover at the inside faces of the line terminals spaced apart at their ends to provide clearances for the free end portions of the line terminals to spring ina disk having a central chamber for receiving a coil spring, one end of which is connected to the disk while the other is yanchored to the cover, contacts on the disk at diametrically opposite pointsl and connected by a conductor, cooperating means on the ldisk and insulation walls to limit movement of the disk relative to the cover, land diametrically spaced means`at the face of the disk opposite the cover for alternately engaging with said latch means.

8. An electric service line protector comprising, in combination, a base of insulating matey engage the free end portions of said terminals,

faces of the line terminals, eachwall having a pointed toe and a shouldered heel and spaced apart circumferentially to provide clearances for permitting the free end portions of the terminal springs to move inwardly, a disk having opposite contacts connected by a conductor adapted to be normally exposed in said clearances to engage the terminals springs, said disk being mounted on the cover within the arcuate members and connected by a coil spring with the cover, a radial projection on the disk movable between spaced abutments on the arcuate insulation walls, and means at the face oi the disk lying next to thelatch for engaging the latter to cause the spring to be fully tensioned when the shouldered heel portions of the insulation walls are engaged with the ends of the line terminals.

JOSEPH E. FARREILr 

